Filled polyketone blend containing a mineral wool fiber

ABSTRACT

Filled polymer compositions comprising a linear alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon and lesser amounts, on a volume basis, of a mineral wool fiber.

FIELD OF THE INVENTION

This invention relates to polyketone polymers, and, more particularly,to a filled polymer compound comprising a major portion of a polyketonepolymer and lesser portions of mineral wool fiber on a volume basis.

BACKGROUND OF THE INVENTION

Polyketone polymers are relatively high molecular weight materialshaving established utility as premium thermoplastics in the productionof shaped articles, such as containers for food and beverages and partsfor the automotive industry, which are produced by processing thepolyketone polymer according to well known methods. For some particularapplications it is desirable to have properties which are somewhatdifferent from those of the polyketone polymers. The more desirableproperties of the polyketone polymers may be retained, and yet otherproperties improved, through the provision of a filled polymer compound.Reinforcing a polymer with a filler often provides a less expensiveproduct, in addition to desirable properties for various applications.

Mineral-filled polyketone compounds with certain desirable propertiesare disclosed in U.S. Pat. No. 4,851,470 (George). The neat polyketonepolymer has an unfortunate tendency to form chemical crosslinks at meltprocessing temperatures, as evidenced by a steady increase in meltviscosity as the polymer is processed. Mineral fillers frequentlypossess a variety of ionic species which are capable of intensifyingmelt processing problems for the polyketone polymer, such asaccelerating crosslinking of the polymer, thereby limiting the meltprocessability of the filled polyketone compounds.

It is an objective of this invention to provide a mineral-filledpolyketone polymer compound that exhibits superior melt stability duringmelt processing. The filled polyketone polymer compounds of the subjectinvention exhibit viscosity levels during processing that areunexpectedly lower than the viscosity levels typical for compoundsfilled with other fibrous mineral fillers, and yet exhibit mechanicalproperties at least equal to those of compounds filled with such otherfibrous mineral fillers.

SUMMARY OF THE INVENTION

The present invention provides certain mineral-filled polymer compoundsof linear alternating polymers of carbon monoxide and at least oneethylenically unsaturated hydrocarbon, filled with mineral wool fiber.The amount of mineral wool fiber present in the filled compounds, on avolume basis, may be from about 5 vol % to about 40 vol %. A preferredmineral wool fiber is a processed mineral fiber containing primarilycalcium silicate and treated to reduce its shot content. In processing,the filled compounds exhibit melt stability superior to that ofcomparable fillers. The compounds demonstrate improved strength andstiffness, as well as dimensional stability. The invention also includesarticles of manufacture prepared from, and coated with, such filledcompounds.

DESCRIPTION OF THE INVENTION

The polyketone polymers which are employed as the major component of thefilled polymer compounds of the invention are of a linear alternatingstructure and contain substantially one molecule of carbon monoxide foreach molecule of unsaturated hydrocarbon. Suitable ethylenicallyunsaturated hydrocarbons for use as monomers in the polyketone polymershave up to 20 carbon atoms inclusive, preferably up to 10 carbon atoms,and are aliphatic such as ethylene and other α-olefins includingpropylene, 1-butene, isobutylene, 1-hexene, 1-octene and 1-dodecene, orare arylaliphatic containing an aryl substituent on an otherwisealiphatic molecule, particularly an aryl substituent on a carbon atom ofthe ethylenic unsaturation. Illustrative of this latter class ofethylenically unsaturated hydrocarbons are styrene, p-methylstyrene,p-ethylstyrene and m-isopropylstyrene. The preferred polyketone polymersare copolymers of carbon monoxide and ethylene or terpolymers of carbonmonoxide, ethylene and a second ethylenically unsaturated hydrocarbon ofat least 3 carbon atoms, particularly an α-olefin such as propylene.

When the preferred polyketone terpolymers are employed as the majorpolymeric component of the blends of the invention, there will be withinthe terpolymer at least about 2 units incorporating a monomer ofethylene for each unit incorporating a monomer of the secondhydrocarbon. Preferably, there will be from about 10 units to about 100units incorporating a monomer of ethylene for each unit incorporating amonomer of the second hydrocarbon. The polymer chain of the preferredpolyketone polymers is therefore represented by the repeating formula

    --CO--CH.sub.2 --CH.sub.2)].sub.x [CO--G)].sub.y

wherein G is the monomer of ethylenically unsaturated hydrocarbon of atleast 3 carbon atoms polymerized through the ethylenic unsaturation andthe ratio of y:x is no more than about 0.5. When copolymers of carbonmonoxide and ethylene are employed in the blends of the invention, therewill be no second hydrocarbon present and the copolymers are representedby the above formula wherein y is zero. When y is other than zero, i.e.,terpolymers are employed, the --CO--CH₂ CH₂ -- units and the --CO--G--units are found randomly throughout the polymer chain, and preferredratios of y:x are from about 0.01 to about 0.1. The end groups or "caps"of the polymer chain will depend upon what materials were present duringthe production of the polymer and whether or how the polymer waspurified. The precise nature of the end groups does not appear toinfluence the properties of the polymer to any considerable extent sothat the polymers are fairly represented by the formula for the polymerchain as depicted above.

Of particular interest are the polyketone polymers of number averagemolecular weight from about 1000 to about 200,000, particularly those ofnumber average molecular weight from about 20,000 to about 90,000 asdetermined by gel permeation chromatography. The physical properties ofthe polymer will depend in part upon the molecular weight, whether thepolymer is a copolymer or a terpolymer and, in the case of terpolymers,the nature of and the proportion of the second hydrocarbon present.Typical melting points for the polymers are from about 175° C. to about300° C., more typically from about 210° C. to about 270° C. The polymershave a limiting viscosity number (LVN), measured in m-cresol at 60° C.in a standard capillary viscosity measuring device, from about 0.5 dl/gto about 10 dl/g, more frequently from about 0.8 dl/g to about 4 dl/g.

U.S. Pat. No. 4,880,903 (VanBroekhoven et al.) discloses a linearalternating polyketone polymer of carbon monoxide, ethylene, and otherolefinically unsaturated hydrocarbons, such as propylene. Processes forproduction of such polyketone polymers typically involve the use of acatalyst composition formed from a compound of a Group VIII metalselected from palladium, cobalt or nickel, the anion of a strongnon-hydrohalogenic acid and a bidentate ligand of phosphorus, arsenic orantimony. U.S. Pat. No. 4,843,144 (VanBroekhoven et al.) discloses aprocess for preparing polymers of carbon monoxide and at least oneethylenically unsaturated hydrocarbon using a catalyst comprising acompound of palladium, the anion of a non-hydrohalogenic acid having apKa of below about 6 and a bidentate ligand of phosphorus.

The carbon monoxide and hydrocarbon monomer(s) are contacted underpolymerization conditions in the presence of a catalyst compositionformed from a compound of palladium, the anion of a non-hydrohalogenicacid having a pKa (measured in water at 18° C.) of below about 6,preferably below 2, and a bidentate ligand of phosphorus. The scope ofthe polymerization is extensive but, without wishing to be limited, apreferred palladium compound is a palladium carboxylate, particularlypalladium acetate, a preferred anion is the anion of trifluoroaceticacid or p-toluenesulfonic acid and a preferred bidentate ligand ofphosphorus is 1,3-bis(diphenylphosphino)propane or1,3-bis[di(2-methoxyphenyl)phosphino]propane.

The polymerization to produce the polyketone polymer is conducted in aninert reaction diluent, preferably an alkanolic diluent, and methanol ispreferred. The reactants, catalyst composition and reaction diluent arecontacted by conventional methods such as shaking, stirring or refluxingin a suitable reaction vessel. Typical polymerization conditions includea reaction temperature from about 20° C. to about 150° C., preferablyfrom about 50° C. to about 135° C. The reaction pressure is suitablyfrom about 1 atomosphere to about 200 atmospheres but pressures fromabout 10 atmospheres to about 100 atmospheres are preferred. Subsequentto polymerization, the reaction is terminated as by cooling the reactorand contents and releasing the pressure. The polyketone polymer istypically obtained as a product substantially insoluble in the reactiondiluent and the product is recovered by conventional methods such asfiltration or decantation. The polyketone polymer is used as recoveredor the polymer is purified as by contact with a solvent or extractionagent which is selective for catalyst residues.

The second component of the filled polymer compounds of the inventioncomprises mineral wool fiber (fiberized blast furnace slag), or rockwool. Particularly preferred are the processed mineral fibers availablefrom Jim Walter Resources, Inc. These processed mineral fibers are amilled form of mineral wool, from which most of the shot (non-fibrousmaterial) has been removed. U.S. Pat. No. 4,026,478 (Albert et al.)describes a process for making such fibers.

The processed mineral fibers comprise primarily calcium silicate, withabout 25 wt % oxides of aluminum, magnesium, and other lightweightmetals also present. Fiber diameters range from about 1 μm, with anaverage diameter of about 5 μm and an average length of about 275 μm.The processed mineral fibers contain less than about 5 wt % non-fibrousmaterial.

Mineral wool fibers, and processed mineral fibers, are synthetic (i.e.manufactured) materials. Most commercial mineral fillers are naturallyoccurring materials, although they may be refined to obtain a particularsize range, and/or coated with a sizing material or coupling agent. Somenaturally occurring mineral fillers, such as asbestos, exist in afibrous form.

The filled polymer compounds of the invention comprise a major amount,on a volume basis, of the linear alternating polymer of carbon monoxideand at least one ethylenically unsaturated hydrocarbon with lesseramounts of mineral wool fiber. The amount of mineral wool fiber presentin the filled compounds of the invention is not critical, as long asother important polymer properties for the intended use are notadversely affected. Amounts of mineral wool fiber present in the filledcompounds, on a volume basis, may be from about 5 vol % to about 40 vol%, based on total composition, with amounts from about 20 vol % to about30 vol % mineral wool fiber preferred. On a weight basis, the amount ofmineral wool fiber present may be greater than 50 wt %, due to itsgreater density. Amounts of mineral wool fiber present in the filledcompounds, on a weight basis, may be from about 10 wt % to about 60 wt %mineral wool fiber, based on total composition, with amounts from about35 wt % to about 50 wt % mineral wool fiber being preferred for a widevariety of uses.

The method of producing the filled polymer compounds of the invention isnot material so long as a relatively uniform distribution of the mineralwool filler throughout the polyketone is obtained. The mineral woolfiber filler exists as a discrete phase in the polyketone matrix. Themethod of producing the compounds is that which is conventional forpolymeric fillers. In one modification, the mineral wool fiber fillerand polyketone are mixed and passed through an extruder operating athigh RPM to produce the filled compound as an extrudate. In an alternatemodification, the components are blended in a mixing device whichexhibits high shear.

The filled polymer compounds of the invention may also include otheradditives such as antioxidants, dyes, other fillers or reinforcingagents, fire resistant materials, mold release agents, colorants andother materials designed to improve the processability of the polymersor the properties of the resulting compound. Such additives are addedprior to, together with, or subsequent to the blending of the polyketoneand mineral wool fiber. The presence of these additives may affect theoptimum level of mineral wool fiber for a given application.

The compounds are processed by methods such as extrusion and injectionmolding into sheets, films, plates and shaped parts. The compositions ofthe invention are particularly useful for the production of articles bymultiple melting/crystallization cycles, and where elevated temperaturesare likely to be encountered. Illustrative of such applications are theproduction of articles useful in both rigid and flexible packagingapplications, and in both internal and external parts for automotiveuse.

While not wishing to be bound by any particular theory, it is believedthat the advantageous results of the invention are obtained because themineral wool fiber has ion exchange and acid scavenging properties thatallow it to neutralize the effect of ionic or acidic species thataccelerate a viscosity increase in the polyketone polymer in the meltstate. Since few polymers exhibit such a tendency towards viscosityincrease, the use of mineral wool fiber as a filler for the polyketonepolymer is particularly advantageous, providing filled compounds thatare readily processable into materials which exhibit useful mechanicalproperties and moderate reinforcement.

The invention is further illustrated by the following Examples whichshould not be regarded as limiting.

EXAMPLE 1

A linear alternating terpolymer of carbon monoxide, ethylene, andpropylene (89/056) was produced in the presence of a catalystcomposition formed from palladium acetate, trifluoroacetic acid and1,3-bis[di(2-methoxyphenyl)phosphino]propane. The polyketone polymer hada melting point of about 223° C. and an LVN of about 1.1 dl/g whenmeasured in m-cresol at 60° C. The polyketone polymer also contained0.5% Ethanox® 330 and 0.5% Nucrel® 535.

EXAMPLE 2

Filled compounds were prepared of the polymer of Example 1 and twodifferent types of mineral wool fiber, with and without a surfacecoating. The first was PMF 204, an untreated processed mineral fiber,and the second was PMF 204CX, a processed mineral fiber treated with alow level of a fatty-acid-type material for improved fiber dispersionduring blending. Both PMF 204 and PMF 204CX were obtained from JimWalton Resources, Inc. For comparison with the filled compounds of theinvention, samples containing wallastonite with two different types ofsurface coating ("A" and "B") and gypsum whisker fibers were prepared inthe same manner. Wallastonite is a naturally occurring calcium silicatemineral, which forms cylindrical particles upon grinding. Gypsum whiskerfibers are manufactured from gypsum (calcium sulfate) and arecommercially available as Franklin Fiber from the United States GypsumCo. The filled compounds prepared are shown in Table 1.

All of the compounds were prepared by tumbling polyketone polymer powderwith the mineral filler at the prescribed composition. Subsequently,melt compounding was performed in a 30 mm Haake co-rotating twin screwextruder, operating at about 200 rpm with a melt temperature of about250° C. The viscosity of each sample was determined over time in themelt in a Rheometrics parallel plate rheometer operating at 275° C. at afrequency of 1 HZ. Table 1 lists the initial melt viscosity and theviscosity after both 10 and 28 minutes, as well as a ratio of the meltviscosity after 28 minutes to the initial melt viscosity.

                                      TABLE 1                                     __________________________________________________________________________             Polyketone                                                                            Filler  Viscosity (Pa-sec)                                                                         Viscosity                               Filler   wt % (vol %)                                                                          wt % (vol %)                                                                          0 min                                                                             10 min                                                                            28 min                                                                             Ratio                                   __________________________________________________________________________    None     100 (100)                                                                             0 (0)    63 113 1030 16                                      PMF 204  80 (90) 20 (10) 185 410 2049 11                                      PMF 204  64 (80) 36 (20) 600 1354                                                                              3453   5.8                                   PMF 204  51 (70) 49 (30) 1800                                                                              3453                                                                              21,640                                                                             12                                      PMF 204CX                                                                              80 (90) 20 (10) 300 650 2872   9.6                                   Wallastonite A                                                                         79 (90) 21 (10)  89 1455                                                                              30,270                                                                             340                                     Wallastonite B                                                                         79 (90) 21 (10)  89 522 7547 85                                      Gypsum Whiskers                                                                        78 (90) 22 (10) 280 668 9919 35                                      __________________________________________________________________________

The addition of a solid filler to the polyketone polymer inherentlyresults in a viscosity increase in the melt state for the filledcompound. Thus, the ratio of melt viscosity after 28 minutes to theinitial melt viscosity provides a relative measure of the viscosityincrease that occurs when various fillers are added to the polyketonepolymer.

The compounds filled with processed mineral fiber demonstrated superiormelt stability, based on these rheometric data, relative to the otherfilled compounds. Only the processed mineral fiber filled compounds gavea viscosity ratio which was less than that of the neat polyketonepolymer, indicating stabilization. The viscosity ratios for thecompounds filled with wallastonite and gypsum whiskers (both commercialfillers) were significantly higher, indicating destabilization in themelt state.

EXAMPLE 3

Subsequent to compounding, specimens of the filled compounds of Example2 were molded into plaques on a 25 ton Arburg injection molding machine.Molded specimens were stored over desicant until testing. Furthertesting was performed on "dry as molded" specimens.

Results of the thermal testing are shown in Table 2. The processedmineral fiber provided a significant improvement in the averagecoefficient of linear thermal expansion (CLTE) over the range from roomtemperature to 200° C., both in the direction parallel to, andperpendicular to the flow pattern in the injection molded test bar. Theheat deflection temperature (HDT, determined at 264 psi) was notsignificantly improved.

                                      TABLE 2                                     __________________________________________________________________________             Polyketone                                                                            Filler  CLTE (ppm/°C.)                                                                      HDT                                     Filler   wt % (vol %)                                                                          wt % (vol %)                                                                          Parallel                                                                           Perpendicular                                                                         (°C.)                            __________________________________________________________________________    None     100 (100)                                                                             0 (0)   147  149     103                                     PMF 204  80 (90) 20 (10) 72   114     107                                     PMF 204  64 (80) 36 (20) 60    87     113                                     PMF 204  51 (70) 49 (30) 50   111     118                                     PMF 204CX                                                                              80 (90) 20 (10) 80   121      97                                     Wallastonite A                                                                         79 (90) 21 (10) 93    92     144                                     Wallastonite B                                                                         79 (90) 21 (10) 82   125     116                                     Gypsum Whiskers                                                                        78 (90) 22 (10) 92    95     109                                     __________________________________________________________________________

Results of the mechanical testing are shown in Table 3. The mechanicalproperty data indicate that processed mineral fiber is an acceptablefiller for the polyketone polymer, and provides filled compounds withproperties which are comparable to those made with other fillers, suchas wallastonite and gypsum whiskers.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of this specification, or by practice ofthe invention described herein. It is intended that the specificationand examples be considered as exemplary only, with the true scope andspirit of the invention being indicated by the following claims.

                                      TABLE 3                                     __________________________________________________________________________                             Flexural                                                                           Flexural                                                                           Tensile    Impact Properties                        Polyketone                                                                            Filler  Modulus                                                                            Strength                                                                           Strength                                                                           Elongation                                                                          Izod Gardner                    Filler   wt % (vol %)                                                                          wt % (vol %)                                                                          (kpsi)                                                                             (psi)                                                                              (psi)                                                                              (%)   (ft-lb/in)                                                                         (in-lbs)                   __________________________________________________________________________    None     100 (100)                                                                             0 (0)   259   9,260                                                                             9,130                                                                              86    1.93 126                        PMF 204  80 (90) 20 (10) 406  10,110                                                                             7,810                                                                              37    1.28 15                         PMF 204  64 (80) 36 (20) 491   9,890                                                                             6,240                                                                              23    0.96 10                         PMF 204  51 (70) 49 (30) 609   9,740                                                                             5,410                                                                              17    0.89  9                         PMF 204CX                                                                              80 (90) 20 (10) 415  10,280                                                                             7,900                                                                              38    1.40 16                         Wallastonite A                                                                         79 (90) 21 (10) 428  11,050                                                                             7,980                                                                              19    1.11  8                         Wallastonite B                                                                         79 (90) 21 (10) 391  10,260                                                                             7,870                                                                              19    1.12 10                         Gypsum Whiskers                                                                        78 (90) 22 (10) 386  10,220                                                                             7,750                                                                              28    1.05 38                         __________________________________________________________________________

What is claimed is:
 1. A filled polymer composition comprising a linearalternating polyketone polymer and from about 5 vol % to about 40 vol %,based on total composition, of a mineral wool fiber.
 2. The compositionof claim 1 wherein the polyketone polymer is of the repeating formula

    --CO--CH.sub.2 --CH.sub.2)].sub.x [CO--G)].sub.y

wherein G is a monomer of an ethylenically unsaturated hydrocarbon of atleast 3 carbon atoms, polymerized through the ethylenic unsaturation,and the ratio of y:x is no more than about 0.5.
 3. The composition ofclaim 2 wherein y is
 0. 4. The composition of claim 2 wherein the ratioof y:x is from 0.01 to about 0.1.
 5. The composition of claim 4 whereinG is a monomer of propylene.
 6. The composition of claim 2 wherein theprocessed mineral fiber is present in a quantity of from about 20 vol %to about 30 vol %, based on total composition.
 7. A filled polymercomposition comprising a linear alternating polyketone polymer and fromabout 5 vol % to about 40 vol %, based on total composition, of aprocessed mineral fiber.
 8. The composition of claim 7 wherein thepolyketone polymer is of the repeating formula

    --CO--CH.sub.2 --CH.sub.2)].sub.x [CO--G)].sub.y

wherein G is a monomer of an ethylenically unsaturated hydrocarbon of atleast 3 carbon atoms, polymerized through the ethylenic unsaturation,and the ratio of y:x is no more than about 0.5.
 9. The composition ofclaim 8 wherein the ratio of y:x is from 0.01 to about 0.1.
 10. Thecomposition of claim 9 wherein G is a monomer of propylene.
 11. Thecomposition of claim 8 wherein y is
 0. 12. The composition of claim 11wherein the processed mineral fiber is present in a quantity of fromabout 20 vol % to about 30 vol %, based on total composition.
 13. Anarticle manufactured from the composition of claim 7.